Charging integrated circuit and operating method

ABSTRACT

A charging integrated circuit (IC) in a mobile device including battery includes; a switching charger including at least one inductor, a direct charger including at least one capacitor, and a control circuit. The control circuit detects a connection between the mobile device and an external power unit and a disconnection between the mobile device and the external power unit, wherein the switching charger and the direct charger selectively receive an external power signal provided by the external power unit by the connection between the mobile device and an external power unit. Upon detecting the connection between the mobile device and an external power unit, the charging IC activates the direct charger and provides a constant charging current to the battery using the direct charger, and upon detecting the disconnection between the mobile device and an external power unit, the charging IC deactivates the direct charger, activates the switching charger, and maintains a battery voltage associated with the battery using the switching charger.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application No.10-2019-0125680, filed in the Korean Intellectual Property Office onOct. 10, 2019, the subject matter of which is hereby incorporated byreference.

BACKGROUND

The inventive concept relates to charging integrated circuits capable ofcontrolling the charging of a battery, and associated operating methods.

Mobile electronic devices (hereafter, mobile devices) are typicallypowered for considerable periods of time by a battery integral to themobile device. However, power demands placed upon the battery haveincreased over time with rising performance and functionality demands.Hence, battery capacity (e.g., the amount of electrical charge thebattery is capable of providing to the mobile device) and battery life(e.g., the time period between successive requirements for batterycharging) have become important design considerations. Different batterycharging options are often provided in view of consumer demands. Hence,mobile devices may be charged at different rates depending on themagnitude (or level) of an applied charging voltage (i.e., the level ofa voltage provided by a charger to the battery of a mobile device).Different battery charging methods may include a rapid charging methodand a general charging method.

SUMMARY

The inventive concept provides a charging IC including a switchingcharger and a direct charger, wherein the charging IC is capable ofefficiently charging a battery without requirement of control by acontrol unit such as an application processor.

According to an aspect of the inventive concept, there is provided acharging integrated circuit (IC) in a mobile device including battery,the charging IC including; a switching charger including at least oneinductor, and a direct charger including at least one capacitor, and acontrol circuit configured to detect a connection between the mobiledevice and an external power unit and a disconnection between the mobiledevice and the external power unit, wherein the switching charger andthe direct charger selectively receive an external power signal providedby the external power unit by the connection between the mobile deviceand an external power unit. Upon detecting the connection between themobile device and an external power unit, the charging IC activates thedirect charger and provides a constant charging current to the batteryusing the direct charger, and upon detecting the disconnection betweenthe mobile device and an external power unit, the charging ICdeactivates the direct charger, activates the switching charger, andmaintains a battery voltage associated with the battery using theswitching charger.

According to another aspect of the inventive concept, there is provideda method of operating a charging integrated circuit (IC) in a mobiledevice including battery. The method includes; upon detecting aconnection between the mobile device and an external power unitproviding an external power signal, activating a direct charger andusing the direct charger to charge the battery with a constant currentassociated with an external power signal during a constant charge (CC)section of a battery charging process, and upon detecting an end of theCC section, charging the battery with a charging power different fromusing the direct charger to charge of the battery with the constantcurrent associated with the external power signal during a constantvoltage (CV) section of the battery charging process.

According to another aspect of the inventive concept, there is provideda mobile device including; a battery embedded in the electronic device,and a charging integrated circuit (IC) chip configured to charge thebattery with a constant current using a direct charger during a constantcurrent (CC) section of a battery charging process, and to hereaftercharge the battery with a constant voltage during a constant voltage(CV) section of the battery charging process,

wherein a level of the constant current is defined by an external powersignal provided by an external power unit when the externa power unit isconnected to the mobile device.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the inventive concept will be more clearly understoodupon review of the following detailed description taken in conjunctionwith the accompanying drawings in which:

FIG. 1 is a block diagram of a mobile device according to an embodimentof the inventive concept;

FIG. 2 is a block diagram further illustrating the charging IC 110 ofFIG. 1 ;

FIGS. 3A, 3B and 15 are respective circuit diagrams further illustratingexamples of the charging IC of FIGS. 1 and 2 ;

FIGS. 4A, 6, 8, 10, 11 and 13 are respective flowcharts summarizing invarious aspects operating methods for a charging IC according toembodiments of the inventive concept;

FIG. 4B is a block diagram illustrating a closed loop formed by thecharging IC according to an embodiment of the inventive concept togetherwith an external power unit and an application processor;

FIGS. 5, 7, 9, 12 and 14 are respective waveform diagrams illustratingcertain relationships graph between a charging current, a batteryvoltage, and a state of charge for a battery consistent with variousoperating methods according to embodiments of the inventive concept;

DETAILED DESCRIPTION

Hereinafter, embodiments of the inventive concept will be described insome additional detail with reference to the accompanying drawings.

Figure (FIG. 1 is a block diagram of a mobile device 100 and an externalpower unit 200 according to an embodiment of the inventive concept. Themobile device 100 and the external power unit 200 may be variouslyconnected in one or more hardwired configurations and/or one or morewireless configurations.

The mobile device 100 may take many different forms, such as a smartphone, a tablet personal computer (PC), a mobile phone, a PersonalDigital Assistant (PDA), a laptop computer, a wearable electronicdevice, a Global Positioning System (GPS) device, an e-book terminal, adigital broadcasting terminal, an MP3 player, a digital camera, anelectronic vehicle, etc. As will be appreciated by those skilled in theart, the term “mobile device” in this context refers to any electronicdevice capable being operated by a user without requirement for thedevice to be continuously hardwire-connected to a power source externalto the device.

In the illustrated example of FIG. 1 , the mobile device 100 includes abattery 130 and a charging integrated circuit (IC) 110 that may bevariously configured to charge the battery 130. Thus, the charging IC110 may be considered to be a battery charger (i.e., a circuit that isused, wholly or in part, to provide electrical charge to a battery).

The charging IC 110 may be variously implemented. For example, thecharging IC may be an integrated circuit chip or set of chips mounted ona printed circuit board (PCB). However physically implemented, thecharging IC 110 may receive an external power signal from the externalpower unit 200. The external power signal may be variously provided inone or more forms (e.g., waveform(s), power level(s), applicationtiming, etc.) consistent with one or more charging requirements and/orapproaches to battery charging.

As suggested by the illustrated example of FIG. 1 , the external powersignal may be applied to the charging IC 110 of the mobile device 100through a receptacle interface 140 using a hardwire connection (e.g.,the travel adaptor 210) or a wireless connection (e.g., the wirelesscharger 220). Regardless of its particular form or connectionconfiguration, the external power signal may be used to charge (i.e.,provide electrical charge and/or electrical current—hereaftergenerically referred to as “charging power”) the battery 130. In theillustrated embodiment of FIG. 1 , the charging IC 110 may be used tocontrol the charging of the battery 130 in the mobile device 100 in viewof a variable system load 120. A more detailed example of the chargingIC 110 will be described hereafter with reference to FIG. 2 .

The battery 130 may take one of many different forms. For example, thebattery 130 may be a multi-cell battery including multiple,series-connected battery cells. Alternately, the battery 130 may be asingle-cell battery including only a single battery cell. Regardless ofthe particular configuration of the battery 130, when the mobile device100 is connected to the external power unit 200, the battery 130 mayreceive charging power through the operation of the charging IC 110.Once the battery 130 is sufficiently charged, the power requirements ofthe variable system load 120 within the mobile device 100 may be meet.

As will be appreciated by those skilled in the art, the system load 120shown in FIG. 1 is a dynamic element that may be understood as aconceptual aggregation of varying power requirements within the mobiledevice 100. That is, the system load 120 may vary with the configurationand/or current operating functions of the mobile device 100. Componentscommonly included in the mobile device 100, albeit not shown in FIG. 1for the sake of clarity, include a display, an application processor, acommunication processor, a speaker, a camera, a memory, and the like.These components, or more particularly the power demand(s) associatedwith the operation of the these components, may be part of the systemload 120. In actual implementation these components variously includeintegrated circuits, chips, modules, operation blocks, functionalblocks, and intellectual property (IP) blocks included in the mobiledevice 100.

Hence, the system load 120 may be understood, at least at one conceptuallevel, as an aggregation of electrical power demand(s) within the mobiledevice 100 that may be fulfilled (or meet) by the battery 130 and/or theexternal power unit 200, if the external power unit 200 is connected tothe mobile device 100.

The receptacle interface 140 may be various configured to connect withthe mobile device 100. For example, the receptacle interface 140 mayconnect the mobile device 100 with the external power unit 200 via auniversal serial bus (USB) cable. In different embodiments of theinventive concept, the receptacle interface 140 may be a USB type-Cinterface, and the USB cable may be a USB type-C cable—where the USBtype-C interface is configured in accordance with the publicly availableand well understood standards, such as those established by USB 2.0 orUSB 3.1. The receptacle interface 140 may include a plurality ofelectrical connection pins (hereafter, “pins”), wherein the pins mayinclude one or more power supply pin(s), data pin(s), and/or channelconfiguration (CC) pin(s), etc.

It should be noted at this point that the external power unit 200 maytake many different forms, provide different connection and powerconfigurations, and/or enable a variety of functions, depending of thedesign of the mobile device 100 and the external power unit 200. Todescribe exemplary battery charging approaches that may be used inrelation to embodiments of the inventive concept, the external powerunit 200 of FIG. 1 is shown as including the travel adaptor 210 and thewireless charger 220, but these are just selected examples. Thoseskilled in the art will recognize that the external power unit 200 mayinclude more, fewer or different components, and correspondingly enabledifferent battery charging approaches.

Recognizing that the external power unit 200 may (or may not) beconfigurable to connect with the mobile device 100 via a hardwireconnection (e.g., a conventional plug-in connection to a 110 AC or 220AC electrical line), the wireless charger 220 may be used to wirelesslyprovide charging power to the mobile device 100. As will further beappreciated by those skilled in the art, there are many differentapproaches to the provision of hardwire and wireless charging power. Forexample, the wireless charger 220 may wirelessly provide charging powerusing a magnetic induction method, a magnetic resonance method, anelectromagnetic induction method, a non-radiative wireless electricity(WiTricity) method, etc.

In certain embodiments of the inventive concept, one or moreconfigurations enabling the connection of the mobile device 100 to anexternal power source using (e.g.) using the travel adaptor 210 areprovided. Thus, when the mobile device 100 is hardwire connected to110/220 AC electrical line, the travel adaptor 210 may be used toconvert the alternating current (AC) power provide by the electricalline into a direct current (DC) power signal compatible with thereceptacle interface 140, the charging IC 110 and/or the battery 130 ofthe mobile device 100. Alternately, the when the mobile device 100 ishardwire connected to a host DC power source (e.g., a computer powersupply), the travel adaptor 210 may be used to convert the host DC powerinto the DC power signal compatible with the receptacle interface 140,the charging IC 110 and/or the battery 130 of the mobile device 100.

According to these exemplary approaches among others, the travel adaptor210 may support a “direct charging” of the battery 130 (e.g., a hardwirepower connection together with voltage, current and/or waveformconversion(s) as required between the external power source and a powersignal internally compatible with mobile device components). As will bedescribed in some additional detail hereafter with reference to FIG. 2 ,an application processor 121 or a direct charger 113 may be used torecognize whether the travel adaptor 210 supports direct charging by(e.g.) monitoring a resistance value for a particular pin (e.g., CC pin141).

FIG. 2 is a block diagram further illustrating in one example the mobiledevice 100, and in particular the charging IC 110 of the mobile device100 according to an embodiment of the inventive concept.

Here, a threshold use of the travel adaptor 210 is assumed, but use ofthe wireless charger 220 might be just as easily assumed. In addition,only the application processor 121 is specifically illustrated as anexample of the variable system load 120 described above in relation toFIG. 1 .

In the illustrated embodiment of FIG. 2 , the charging IC 110 mayinclude a control circuit 112, a direct charger 113, a switching charger114, an interrupt control logic (ICL) 111, a fuel gauge 116, and a powermeter 115.

The ICL 111 may be used to control the magnitude (or level) of one ormore input current(s) and/or one or more input voltage(s) (hereafterreferred to in any combination as, “input voltage/current”). Here, forexample, it is assumed that an input voltage/current provided at a powerpin 142 of the receptable interface 140 is connected via a bus (Vbus)through the ICL 111 to the direct charger 113 and the switching charger114.

When the system load 120 demands relatively high levels of power duringa time when the battery 130 is being charged, the level of the inputvoltage/current provided to the charging IC 110 must be sufficient tomeet the power demands of both the system load 120 and the charging ofthe battery 130. However, if the level of the input voltage/currentrises too much, there is a danger of overloading the charging IC 110,and in extreme cases even starting a fire or causing an explosion.Accordingly, the ICL 111 may be used to control the level of the inputvoltage/current such that it never exceeds a defined safety threshold.

In certain embodiments of the inventive concept, the ICL 111 may includean internal transistor resistor. Assuming this particular configuration,should the level of the input voltage/current exceed the safetythreshold, the resistance of the internal transistor resistor may beadjusted in response to a control signal (e.g., a part of the controlinformation provided by the control circuit 112). Thus, assuming thatthe voltage level of the external power signal provided by the externalpower unit 200 remains constant, the input voltage/current level may besafely controlled by adjusting the resistance of the internal transistorresistor of the ICL 111.

The control circuit 112 may be used to control the overall operation ofthe charging IC 110. Here, the control circuit 112 may controlcommunication between the charging IC 110 and he the travel adaptor 210.In this manner, the control circuit 112 may communicate various controlinformation to the travel adaptor 210 that may be used to define thecharacteristics (e.g., level, waveform, timing, etc.) of the externalpower signal provided by the travel adaptor 210.

In certain embodiments of the inventive concept, the control circuit 112may be used to identify a connection (or non-connection) between thetravel adaptor 210 and the mobile device 100. The control circuit 112may also be used to identify the operating characteristics of the traveladaptor 210. Such identification of the travel adaptor 210 connectionand/or operation may be performed by monitoring one or more pins of thereceptacle interface 140 (e.g., CC pin 141).

In certain embodiments of the inventive concept, the switching charger114 may include a buck converter 320 which may be used to step-down (orstep-up) the level of the input voltage/current. The buck converter 320may also be used to control a period (or cycle) of a charging currentapplied to the battery 130.

In certain embodiments of the inventive concept, the switching charger114 may include an inductor, and may not remove (or prevent) a switchingloss and/or conduction loss due to a resistive component of theinductor. Accordingly, a charging efficiency of the switching charger114 may be less than a charging efficiency of the direct charger 113.

The direct charger 113 may be used to directly provide an inputvoltage/current to the battery 130 via a cap divider 310. (See, e.g.,FIG. 3A). The direct charger 113 may include a transistor and acapacitor, and may reduce the switching loss and/or conduction loss dueto the resistive component of the conductor. The direct charger 113 maydirectly provide the input voltage/current to a node (or terminal) ofthe battery 130 through the cap divider 310, and thus, the directcharger 113 may be suitable for a high-efficiency charging of thebattery 130. For example, charging of the battery 130 with the switchingcharger 114 may have an efficiency of about 90%, whereas charging of thebattery 130 with the direct charger 113 may have an efficiency rangingfrom about 96% to about 98%.

The fuel gauge 116 may be used to sense the power state (or chargestate) of the battery 130. For example, the fuel gauge 116 may sense astate of charge (SoC) for the battery 130 in accordance with a chargingvoltage, a charging current, and/or a battery temperature, etc. The SoCmay be expressed as a ratio of a current capacity with respect to amaximum capacity of the battery 130, and may be defined in percentage(%) units.

In certain embodiments of the inventive concept, the fuel gauge 116 mayinclude an analog-to-digital (ADC) converter, such that the fuel gauge116 may digitally convert analog signal level(s) (e.g., sensed voltage,sensed current, and/or sensed temperature) into corresponding digitalvalues and provide the digital values to the direct charger 113 and/orthe application processor 121. The fuel gauge 116 may be implementedusing an integrated circuit chip (or portion thereof) mounted on a PCB.However, the inventive concept is not limited thereto, and the fuelgauge 116 and the charging IC 110 may respectively include differentintegrated circuits or integrated circuit chips.

The power meter 115 may be used to monitor information associated withthe input voltage/current. For example, the power meter 115 may be usedto sense (or measure) the level of the input voltage/current applied tothe charging IC 110. Alternately or additionally, the power meter 115may be used to sense (or measure) the level of an output voltage/currentprovided to the system load 120.

An ADC associated with the power meter 115 may be used to convert analoginformation regarding the sensed input voltage/current and/or outputvoltage/current into corresponding digital values and provide theresulting digital values to the application processor 121 and/or thedirect charger 113. The power meter 115 may be implemented using anintegrated circuit chip (or portion thereof) mounted on a PCB. However,the inventive concept is not limited thereto, and the power meter 115and the charging IC 110 may respectively include different integratedcircuits or integrated circuit chips.

Given the foregoing exemplary configuration, the charging IC 110 mayperform mode switching between the direct charger 113 and the switchingcharger 114 in response to control information derived from theoperation of the fuel gauge 116 and/or the power meter 115.

In order to be properly operated under certain power savingcondition(s), the charging IC 110 may further include one or morecircuit(s) supporting at least one of various functions, including anunder-voltage lockout (UVLO) function, an over-current protection (OCP)function, an over-voltage protection (OVP) function, a soft-startfunction to reduce an in-rush current, a foldback current function, ahiccup mode function protecting from a short circuit, anover-temperature protection (OTP) function, etc.

In the regards to the illustrated example of FIG. 2 , it should be notedthat the direct charger 113 and the switching charger 114 may in certainembodiments of the inventive concept be commonly fabricated (orimplemented) in a semiconductor substrate.

FIG. 3A is a circuit diagram further illustrating in one example thecharging IC 110 of FIGS. 1 and 2 according to an embodiment of theinventive concept.

Referring to FIG. 3A, the switching charger 114, the direct charger 113,and the battery 130 are shown in some additional detail.

According to certain embodiments of the inventive concept, the switchingcharger 114 and the direct charger 113 may share an input power unit.Thus, referring to FIG. 3A, a first transistor TR1 may be connectedbetween hardwire input power CHGIN and a first node ND1, where the inputpower CHGIN may correspond to the external power signal provided by thetravel adaptor 210 of FIG. 1 . A second transistor TR2 may be connectedbetween a wireless input power WCIN and the first node ND1, where thewireless input power WCIN may correspond to the external power signalprovided by the wireless charger 220 of FIG. 1 .

The first node ND1 may be connected to the cap divider 310 via a sixthtransistor TR6 and a tenth transistor TR10 and may be connected to thebuck converter 320 via a third transistor TR3.

When the third transistor TR3 is turned OFF, the input power may beprovided to the cap divider 310 and the battery 130 via the input powerunit. That is, when disconnected from the buck converter 320, thecharging IC 110 may operate as the direct charger 113.

When the sixth transistor TR6 and the tenth transistor TR10 arerespectively turned OFF, the input power is provided to the buckconverter 320 via the input power unit, and the input power may beprovided to the battery 130 as the third transistor TR3 and the fourthtransistor TR4 are alternately and repeatedly turned ON/OFF at a regularcycle. That is, when disconnected from the cap divider 310, the chargingIC 110 may operate as the switching charger 114.

Alternately, when the fifth transistor TR5 is turned OFF, the inputpower is provided to the cap divider 310 and the buck converter 320 viathe input power unit, and in this case, the cap divider 310 may chargethe battery 130 and the buck converter 320 may provide system power of afirst output node ND2.

The switching charger 114 may include the third transistor TR3 through afifth transistor TR5 and an inductor L. For example, the thirdtransistor TR3 through the fifth transistor TR5 may include powerswitches. However, the structure of the switching charger 114 is notlimited thereto, and according to embodiments, the number of transistorsand the number of inductors included in the switching charger 114 may bevariously modified. The third transistor TR3 may be connected betweenthe first node ND1 and a switching node LX and receive the input currentthrough the first node ND1. The fourth transistor TR4 may be connectedbetween the switching node LX and a ground node GND and provide a groundvoltage to the switching node LX. The inductor L may be connectedbetween the switching node LX and the first output node ND2. The fifthtransistor TR5 may be connected between the first output node ND2 and asecond output node ND3. The fifth transistor TR5 may receive a voltagefrom the inductor L via the first output node ND2 and provide thereceived voltage to the battery 130 via the second output node ND3. Whenthe fifth transistor TR5 is turned ON, a charging current may beprovided to the battery 130 via the second output node ND3. In addition,in an embodiment, when the fifth transistor TR5 is turned ON, a batterycurrent from the battery 130 may be provided to the system load 120. Thebattery current may flow in an opposite direction of a direction inwhich the charging current flows.

The direct charger 113 may include a first capacitor C1, a secondcapacitor C2, and sixth through thirteenth transistors TR6 through TR13.The cap divider 310 may also be referred to as a current doubler or aninverting charge pump. Referring to FIG. 3A, in a charging processaccording to a direct charging method, switching operations of the sixthtransistor TR6 through the thirteenth transistor TR13 in the firstcapacitor C1 and the second capacitor C2 may be controlled. For example,the second capacitor C2 may be discharged while the first capacitor C1is being charged, and the second capacitor C2 may be charged while thefirst capacitor C1 is being discharged. Accordingly, an output nodevoltage VOUT provided to the battery 130 may maintain an approximatelyconstant level. A value of the output node voltage VOUT may be half avoltage level of the first node ND1.

FIG. 3B is another circuit diagram further illustrating in anotherexample the charging IC 110 of FIGS. 1 and 2 according to an embodimentof the inventive concept.

Referring to FIG. 3B, the charging IC 110 may again include theswitching charger 114, the direct charger 113, and the battery 130. Thecharging IC 110 shown in FIG. 3B may correspond to a modified version ofthe charging IC 110 of FIG. 3A. Compared to the charging IC 110 of FIG.3A, the charging IC 110 of FIG. 3B does not necessarily include thesecond capacitor C2 and the tenth transistor TR10 through the thirteenthtransistor TR13.

Referring to FIG. 3B, while the sixth transistor TR6 and an eighthtransistor TR8 are turned ON, a seventh transistor TR7 and a ninthtransistor TR9 may be turned OFF, and the first capacitor C1 may becharged in a corresponding section. In addition, while the sixthtransistor TR6 and the eighth transistor TR8 are turned OFF, the seventhtransistor TR7 and the ninth transistor TR9 may be turned ON, and thefirst capacitor C1 may be discharged in a corresponding section.Operations in the corresponding sections may be repeatedly performed, avoltage level of the second output node ND3 repeatedly increases anddrops in a certain range, and a voltage of the second output node ND3may be provided to the battery 130.

Referring to FIGS. 3A and 3B, the cap divider 310 is shown as includingthe described plurality of transistors and at least one capacitor, butthe cap divider 310 is not limited thereto. According to certainembodiments of the inventive concept, the cap divider 310 may alsoinclude a single transistor. However, when the cap divider 310 includesa single transistor, a voltage value of the first node ND1 may bedirectly transmitted as a voltage value of the second output node ND3.Accordingly, as a voltage apparent at the second node ND3 fluctuates asmuch as a change in a voltage apparent at the second output node ND3, itmay be difficult to satisfy a condition of maintaining a constantvoltage level in a constant voltage section.

FIG. 4A is a flowchart summarizing in one example an operating methodfor the charging IC 110 according to an embodiment of the inventiveconcept.

Referring to FIGS. 1, 2 and 4A, the operating method begins with thecharging IC 110 detecting the connection of the travel adaptor (TA) 210(S110). The detection may be made in response to (e.g.) a mechanicalplug-in connection of the travel adaptor 210 to the receptacle interface140. That is, when the travel adaptor 210 is mechanically connected tothe mobile device 100 via a hardwire connection (e.g., a cableconnection), the charging IC 110 may identify the connection bymonitoring a particular connection pin (e.g., CC pin 141) associatedwith the receptacle interface 140.

The charging IC 110 may perform charging by using the direct charger 113(S120). In this regard, the charging IC 110 may communicate, asrequired, with the travel adaptor 210 via one or more connection pins(S130), such that the travel adapter 210 communicates (i.e., receivesand/or transmits) control information via the one or more connectionpins.

Alternately, the wireless charger 220 may be used to generate andprovide the external power signal to the mobile device 100. Regardlessof the manner in which the external power signal is generated, however,the control information exchanged between the external power unit 200and the mobile device 100 may include not only connection information,but also power level information that may be used to control thecharacteristics of an input voltage/current and/or an outputvoltage/current.

In this manner, while direct charging of the battery 130 is beingperformed, the application processor 121 may receive control informationassociated with the temperature of the battery 130, the remaining chargeof the battery 130, a charging current and/or charging voltage sensed bythe fuel gauge 116, etc. Accordingly, when it is determined that thetemperature of the battery 130 is too high, for example, the applicationprocessor 121 may communicate relevant control information to theexternal power unit 200 to properly control (e.g., decrease the levelof) the external power signal provided to the mobile device 100.

Returning to flowchart of FIG. 4A and assuming use of the travel adaptor210, the charging IC 110 may determine whether or not the travel adapter210 has been disconnected (S140) as one example of a mechanicaldisconnection between the external power unit 200 and the mobile device100. For example, the charging IC 110 may periodically transmit arequest signal REQ to determine whether or not communication with thetravel adapter 210 is still possible. When the request signal REQ isreceived, the travel adaptor 210 may operate to respond to the chargingIC 110 with an acknowledgment signal ACK, such that the charging IC 110may identify a continuing (or not) communications connection with thetravel adapter 210. Accordingly, when the charging IC 110 does notreceive the acknowledgement signal ACK after a predefined time periodfollowing the request signal REQ, the charging IC 110 may identify thatthe travel adapter 210 has been disconnected (S140=YES).

Upon determining that the travel adapter 210 has been disconnected(S140=YES), the charging IC 110 may deactivate the direct charger 113and instead activate the switching charger 114 (S150).

If the travel adaptor 210 continuously provides the external powersignal to the mobile device 100, it is possible that an overvoltageand/or overcurrent condition may occur possibly resulting in a batteryfire or explosion, or a malfunction in the mobile device 100. Therefore,the charging IC 110 may deactivate the direct charger 113—which directlyapplies charging power to the battery 130 through the second output nodeND3—to prevent the possibility of an overvoltage condition. And instead,the charging IC 110 may charge the battery 130 by activating theswitching charger 114.

FIG. 4B is another block diagram, like the block diagram of FIG. 2 ,further illustrating a closed loop formed by the charging IC 110, theexternal power unit 200 and the application processor 121 according toan embodiment of the inventive concept.

Referring to FIG. 4B, the closed loop formed when the travel adapter 210is connected to and communicates with the mobile device 100 in thefeedback structure. That is, the travel adaptor 210 may provide theexternal power signal (e.g., an input voltage/current) consistent withthe power demands of the mobile device 100. The external power signalprovided by the travel adaptor 210 through the receptacle interface 140may be applied to the direct charger 113 via the ICL 111. In thismanner, the cap divider 310 of the direct charger 113 may be used tocharge the battery 130 with a charging power (e.g., a charging powerassociated with one-half of the level of the external power signalprovided by the travel adapter 210).

Within this configuration, the fuel gauge 116 may be used to sense thestate of charge for the battery 130 and transmit corresponding controlinformation to the application processor 121.

When it is determined that the system load 120 demands an increasedpower signal, the application processor 121 may request that the traveladaptor 210 provide the external power signal with an increased level.That is, a closed-loop feedback structure may be formed in order tocontrol the output of the travel adaptor 210 using the receptacleinterface 140, the direct charger 113, the battery 130, the fuel gauge116, the application processor 121, and the travel adaptor 210. And thisclosed-loop feedback structure may be used to prevent over-charging ofthe battery 130 together with the attendant risks of fire and explosion.

According to certain embodiments of the inventive concept, when thetravel adapter 210 is disconnected, the application processor 121 mayreceive control information identifying a non-connection condition forthe travel adaptor 210, and accordingly release the closed-loop feedbackstructure. However, as will be described in some additional detail withrespect to FIGS. 6, 8, 10, and 13 , even when the travel adapter 210 isdisconnected and the application processor 121 is no longer controlledby control information associated with the travel adaptor 210, thetravel adaptor 210 may nonetheless be used to independently control theexternal power signal and may independently operate to provide stablebattery charging.

FIG. 5 is a waveform diagram illustrating certain signal relationshipsaccording to an embodiment of the inventive concept. A charging currentI_(CHG), a battery voltage V_(BAT), and a state of charging SoC areillustrated and may be understood as corresponding to the operatingmethod described in relation to FIG. 4A.

Referring to FIGS. 1, 2, 3A, 4A and 5 , the charging IC 110 may identifya connection between the travel adaptor 210 and the mobile device 10 attime T1. Between time T1 and time T2, the charging IC 110 may performcharging of the battery 130 using the direct charger 113. As the directcharger 113 directly applies a high voltage to the third node ND3connected to the battery 130, the charging current I_(CHG) may have arelatively high level. Thus, the time period between times T1 and T2 maybe understood as a constant current (CC) section, wherein the battery130 is charged by a current having a relatively high and constant level.

However, at time T2 it is assumed that the charging IC 110 identifies adisconnection of the travel adaptor 210. For example, the charging IC110 may fail to receive an acknowledge signal ACK from the traveladaptor 210 in response to a communicated request signal REQ after apredetermined time. In order to prevent the battery voltage from beingcharged beyond a safety threshold (e.g., a defined maximum batteryvoltage Vmax), the charging IC 110 may deactivate the direct charger 113and activate the switching charger 114.

Between time T2 and time T4, the charging IC 110 may perform charging ofthe battery 130 using the switching charger 114. Charging efficiency ofthe switching charger 114 is less than the charging efficiency of thedirect charger 113, and thus, the battery voltage V_(BAT) and thecorresponding state of charging SoC rise relatively slowly between timeT2 and time T4.

Time T3 corresponds to a time at which the battery voltage V_(BAT) wouldhave reached the maximum battery voltage Vmax if the travel adapter 210had not been disconnected. Thus, the battery charging time may beextended from time T3 to time T4 once the travel adaptor 210 isdisconnected, and the battery charging mode is switched from the directcharger 113 to the switching charger 114.

The period between time T4 and time T5 may be understood as a constantvoltage (CV) section. That is, as the battery voltage V_(BAT) graduallyreaches the maximum battery voltage Vmax at time T4, the charging IC 110may continue to gently charge the battery 130 to maintain the maximumbattery voltage Vmax. Thus, during the CV section, the battery 130 maybe charged to have a constant level equal to the maximum battery voltageVmax, and thus, the charging current I_(CHG) may rapidly decrease, andthe state of charge SoC may remain saturated at a 100% level.

FIG. 6 is a flowchart summarizing in another example an operating methodfor the charging IC 110 according to an embodiment of the inventiveconcept.

Referring to FIG. 6 , the charging IC 110 may detect a plug-in of thetravel adaptor 210 (S210) as one example of a mechanical connectionbetween the external power unit 200 and the mobile device 100. Thecharging IC 110 may perform charging by using the direct charger 113(S220). Here, steps S210 and S220 correspond respectively to steps S110and S120 described in relation to FIG. 4A.

The charging IC 110 may detect an end to a constant current (CC) sectionof the battery charging process (S230), where the CC section correspondsto a period of time during which the battery 130 is charged with acharging current having a constant level. Here, the end of the CCsection may occur when the battery voltage V_(BAT) reaches the maximumbattery voltage Vmax. That is, the fuel gauge 116 may periodicallyperform sensing with respect to the battery 130 to monitor the level ofthe battery voltage V_(BAT) and provide corresponding controlinformation regarding the battery voltage V_(BAT) to the direct charger113.

More particularly, the direct charger 113 may include a direct chargerintellectual property (IP), where the direct charger IP is a circuitimplemented at a logic gate level and may be embedded in the charging IC110 prior to performing the battery charging process according toembodiments of the inventive concept. Hereinafter, description relatedto providing control information to the direct charger 113 or making adetermination in relation to the direct charger 113 may be understood asproviding control information or making a determination in relation tothe IP of the direct charger 113.

Once the end of the CC section has been detected (S240), the charging IC110 may deactivate the direct charger 113 and activate the switchingcharger 114 (S250). That is, when the level of the battery voltageV_(BAT), as sensed by the fuel gauge 116, reaches a level of the maximumbattery voltage, the direct charger 113 may turn OFF the sixthtransistor TR6 and the tenth transistor TR10 in order to activate theswitching charger 114.

In this regard, the charging IC 110 may continue to perform charging ofthe battery 130 during a constant voltage (CV) section of the chargingprocess using the switching charger 114. By deactivating the directcharger 113—which directly applies charging power one or more nodes (orterminals) of the battery 130, the charging IC 110 may instead performcharging using the switching charger 114, such that the battery voltagemay be controlled to stably maintain at or approximate to the level ofthe maximum voltage value in the CV section.

FIG. 7 is a waveform diagram further illustrating certain signalrelationships according to an embodiment of the inventive concept. Here,the charging current I_(CHG), the level of the battery voltage V_(BAT),and the state of charge SoC are shown in relation to the operatingmethod of FIG. 6

Referring to FIG. 7 , the time period between time T1 and time T2 may beunderstood as a constant charge (CC) period, wherein the charging IC110, upon identifying a connection with the travel adaptor 210, performscharging of the battery 130 using the direct charger 113. As the directcharger 113 may directly apply voltage having a relatively high level tothe third node ND3 connected to the battery 130, the charging currentI_(CHG) may have a relatively high level. Thus, during the CC section ofthe battery charging process between time T1 and time T2, the chargingIC may control the charging of the battery 130 to apply and maintain acharging current having a constant level. Hence, the charging of thebattery voltage V_(BAT) may have a constant, positive slope.

At time T2, it is assumed that the charging IC 110 identifies that thelevel of the battery voltage V_(BAT) has reached the maximum batteryvoltage Vmax. In other words, the fuel gauge 116 may be used to sensethe level of the battery voltage V_(BAT) and provide correspondingcontrol information regarding the level of the battery voltage V_(BAT)to the direct charger 113. The direct charger 113 may then be deactivateat time T2. As the level of the battery voltage V_(BAT) reaches themaximum battery voltage Vmax, the battery voltage V_(BAT) maynonetheless be stably and constantly maintained by activating theswitching charger 114.

During the time period (i.e., a constant voltage (CV) section of thebattery charging process) between time T2 and time T3, the charging IC110 may perform charging of the battery 130 using the switching charger114. While the battery voltage V_(BAT) is being maintained, the level ofthe charging current applied to the battery 130 may rapidly decrease. Inaddition, referring to the state of charge SoC, as the level of thecharging current decreases, the slope at which the state of charge SoCincreases also decreases over time.

FIG. 8 is a flowchart summarizing in yet another example an operatingmethod for the charging integrated circuit according to an embodiment ofthe inventive concept. FIG. 9 is another waveform diagram illustratingrelationships between signals during a battery charging processcorresponding to the operating method of FIG. 8 .

Referring to FIG. 8 , method steps S210, S220 and S230 have previouslybeen described with reference to FIG. 6 .

However, following the detection of the end of the CC section of thebattery charging process, the charging IC 110 may be used to control aresistance of the ICL 111 (S260). That is, instead of deactivating thedirect charger 113 and activating the switching charger 114 at the endof the CC section, the charging IC may continue to charge the battery130 using the direct charger 113, but also control the resistance of theICL 111 to maintain a constant voltage level during the CV section ofthe battery charging process. This approach recognizes the lessercharging efficiency of the switching charger.

For example, the charging IC 110 may increase the resistance of the ICL111 proportional with an amount of decrease in the charging currentI_(CHG) during the CV section. Referring to FIG. 9 , if the resistanceof the ICL 111 increases in proportion with an amount of increase in thecharging current I_(CHG), a constantly maintain battery voltage V_(BAT)level may be provided across the CV section. Accordingly, charging ofthe battery 130 using the direct charger 113 may be performed until thebattery 130 is completely charged. However, when the resistance value ofthe ICL increases, the level of power transmission loss due to theresistance of the ICL 11 may also increase.

FIG. 10 is another flowchart summarizing in yet another example anoperating method for the charging IC 110 according to an embodiment ofthe inventive concept.

Referring to FIG. 10 , method steps S210, S220, S230 and S240 havepreviously been described with reference to FIG. 6 .

Additionally, however, in the method of FIG. 10 , the charging IC 110performs a step CC algorithm after detecting the end of the CC section(S340). The step CC algorithm may be an algorithm that graduallydecreases the level of the charging current while maintaining theabove-described characteristics of the CC section. By maintainingcharging time using the direct charger 113 to a greatest extent safelypossible throughout the CC section, the time required for batterycharging may be reduced and charging efficiency improved.

A determination may be made as to whether or not the performing of thestep CC algorithm is complete (S350). In one approach, the fuel gauge116 may be used to provide control information associated with one ormore of the level(s) of the battery voltage V_(BAT) and the chargingcurrent I_(CHG). The direct charger 113 may be used to monitor the levelof the charging current I_(CHG) as sensed by the fuel gauge 116. Whenthe level of the charging current I_(CHG) decreases to be less than orequal to a threshold current value, the direct charger 113 may determinethat the performing of the step CC algorithm is complete (S350=YES).

Although the battery voltage V_(BAT) may actually reach the maximumbattery voltage Vmax, the section of the battery charging process havinga high charging efficiency may be extended by continued use of thedirect charger 113. However, when the charging current I_(CHG) decreasesbelow the threshold current value, the charging efficiency of the directcharger 113 in conjunction with the performing of the step CC algorithmbecomes essentially the same as the charging efficiency of the switchingcharger 114. As will be described in some additional detail hereafter,the charging current I_(CHG) may be reduced by increasing the resistanceof the ICL 111. Conduction loss also occurs in proportion with theincreased resistance of the ICL 111, and thus, charging efficiencydecreases. Thus, a “threshold current value” may be understood as acurrent value at which a first charging efficiency provided by use ofthe direct charger 113 in conjunction with a decreased charging currentI_(CHG), and a second charging efficiency provided by use of theswitching charger 114 are the same. In this regard, the thresholdcurrent value may be determined using well understood experimentalmethods. Alternatively, the threshold current value may be a currentvalue calculated by using information provided by the power meter 115and/or the fuel gauge 116.

FIG. 11 is a flowchart further illustrating in one example the methodsteps of performing the step CC algorithm (S340) and determining whetheror not the step CC algorithm is complete (S350) according to anembodiment of the inventive concept.

Referring to FIG. 11 , the charging IC 110 may determine whether thebattery voltage V_(BAT) has reached the maximum battery voltage Vmax(S341). In this regard, the direct charger 113 may be used to monitorthe battery voltage V_(BAT) (e.g., periodically obtain sensing dataassociated with the battery 130, as provided by the fuel gauge 116. Asnoted above, the sensing data may include the level of the batteryvoltage V_(BAT), the battery temperature, the state of charge SoC forthe battery, etc. The direct charger 113 may also be used to determinewhether the level of the battery voltage V_(BAT) has reached the maximumbattery voltage Vmax based on the obtained sensing data. In one example,the maximum battery voltage Vmax may be defined as 4.2 V.

So long as the level of the battery voltage V_(BAT) remains less thanthe maximum battery voltage Vmax (S341=NO), the direct charger 113 maycontinue to perform monitoring of the battery voltage V_(BAT). However,when the battery voltage V_(BAT) reaches the maximum battery voltageVmax, the direct charger 113 may decrease the charging current I_(CHG)being applied to the battery 130 (S342).

In this regard, the direct charger 113 may transmit a control signal tothe control circuit 112 to instruct decrease the magnitude of theexternal power signal provided by the external power unit 200. Uponreceiving the control signal from the direct charger 113, the controlcircuit 112 may communicate appropriate control information to theexternal power unit 200 (e.g., the travel adaptor 210) via the one ormore CC pins. The control information may include information thatsteps-down the external power signal, and as the external power signaldecreases, the charging current I_(CHG) applied to the battery 130 alsodecreases.

The charging IC 110 may then determine whether the charging currentI_(CHG) is less than the threshold current value (S343). As describedabove, the value of the charging current I_(CHG) may be identified inresponse to sensing data associated with the battery 130, such as thatprovided by the fuel gauge 116. The threshold current value may becalculated in advance and correspond to a current value at which thefirst charging efficiency of the direct charger 113 and the secondcharging efficiency of the switching charger 114 are the same.

So long as the charging current I_(CHG) remains greater than thethreshold current value (S5343=NO), the first charging efficiency of thedirect charger 113 will be stepped-down (yet still remaining greaterthan the second charging efficiency of the switching charger 114) bycyclical repletion of the method steps (S5341=YES), S342 and (S5343=N0).However, when the charging current I_(CHG) falls below the thresholdcurrent value (S5343=YES), a determination may be made that the secondcharging efficient of the switching charger 114 is at least equal to thefirst charging efficiency of the direct charger 113. Accordingly, thedirect charger 113 may be deactivated and the switching charger 114 maybe activated (S240).

FIG. 12 is another waveform diagram illustrating relationships betweensignals during a battery charging process corresponding to the operatingmethod of FIG. 8 according to an embodiment of the inventive concept.

Referring to FIG. 12 , the charging IC 110 may perform charging usingthe direct charger 113 between time T1 and time T2 (a constant charge(CC) section of the battery charging process). In particular, thecharging IC 110 may detect (e.g.) a hardwire connection between theexternal power unit 200 and the mobile device 100 at time T1. The directcharger 113 may be used to directly apply the external power signalprovided by the travel adaptor 210 through the cap divider 310 to thethird node ND3 connected to the battery 130. Under these conditions thelevel of the charging current I_(CHG) may be relatively high.

However, during a sequence of stepped voltage reductions (e.g., T2through T6) (collectively, a step CC section of the batter chargingprocess) a charging voltage/current provided by the direct charger 113may be step-wise reduced. Thus, it is assumed that at time T2 thebattery voltage V_(BAT) reaches the maximum battery voltage Vmax.Referring to FIG. 5 , CV charging using the switching charger 114 may beperformed until the battery voltage V_(BAT) reaches the maximum batteryvoltage Vmax (time T4 of FIG. 5 ), and then the charging current I_(CHG)rapidly decreases. On the other hand, in the step CC section, thecharging IC 110 bypasses activating the switching charger 114 andperforms CV charging using the direct charger 113, while step-wisedecreasing the charging I_(CHG) to decrease the charging I_(CHG) to besimilar to the decrease in charging current I_(CHG) in FIG. 5 .

At time T2, the charging IC 110 may identify that the battery voltageV_(BAT) has reached the maximum battery voltage Vmax and decrease thelevel of the external power signal provided by the travel adaptor 210.For example, the direct charger 113 may obtain sensing data regardingthe battery 130 from the fuel gauge 116 and transmit the controlinformation instructing a decrease in the external power signal via thecontrol circuit 112. As the external power signal passes through the capdivider 310 of the direct charger 113 and is passed at a half value tothe third node ND3, the charging current I_(CHG) may decrease at timeT2. Here, the smaller the decrease in the level of the external powersignal, the shorter the period during which the external power unit 200steps down the external power signal. In this manner, the decrease inthe external power signal will match the graph of the charging currentI_(CHG) in the CV section during charging using the switching charger114. As the direct charger 113 directly provides a charging voltage tothe battery 130 via the third node ND3, the external power signalprovided by the travel adaptor 210, as stepped down at time T2 may havethe desired effect on the battery voltage V_(BAT). Referring to FIG. 10, it may understood that the battery voltage V_(BAT) is also steppeddown by a constant magnitude at time T2.

Between time T2 and time T3, as the charging current I_(CHG) is applied,the battery voltage V_(BAT) may increase. However, the amount ofincrease for the battery voltage V_(BAT) is extremely small, and thelevel of the charging current I_(CHG) may decrease to be similar to thelevel of the charging current I_(CHG) in the CV section. In other words,referring to the state of charge SoC for the battery, it may beunderstood that despite that the battery voltage V_(BAT) increasingduring the time period between time T2 and time T3, the state of chargeSoC increases gradually as in the CV section. The successive timeperiods—the time period from T3 to time T4, the time period from T4 totime T5, and the time period from time T5 to time T6 may be similarlydescribed.

According to the above-described embodiments, after the battery voltageV_(BAT) reaches the maximum battery voltage Vmax and the CC sectionends, the charging IC 110 may perform the step CC algorithm to increasehigh-efficiency charging time using the direct charger 113.

FIG. 13 is another flowchart summarizing in yet another example anoperating method for the charging IC 110 according to an embodiment ofthe inventive concept.

Referring to FIG. 13 , method steps S210, S220 and S342 have previouslybeen described with reference to FIGS. 6, 10 and 11 .

Referring to FIG. 13 , after method steps S210 and S220, the charging IC110 may obtain battery temperature information for the battery 130(S430). The fuel gauge 116 may once again be used to accomplish thisstep. That is, the fuel gauge may periodically obtain sensing dataassociated with the battery 130. The sensing data may include thebattery temperature, the SoC for the battery, and/or the level of thebattery voltage V_(BAT). In certain embodiments of the inventiveconcept, the fuel gauge 116 may provide the sensing data regarding thebattery temperature to the direct charger 113.

Here, the term “battery temperature information” may include at leastone of; a temperature of the battery, an internal temperature taken at apoint within the charging IC 110 (e.g., the application processor 121 orthe system load 120), an external temperature taken at a point outsideof charging IC 110, an internal temperature taken at a point within themobile device 100, etc. For example, the external temperature of thecharging IC 110 and the internal temperature of the mobile device 100may be used to measure, calculate or derive the battery temperatureinformation.

Once the battery temperature information has been obtained, the chargingIC 110 may determine whether the battery temperature exceeds the highthreshold temperature (S440). For example, the direct charger 113 maycompare the high threshold temperature with the battery temperatureinformation using the fuel gauge 116. The high threshold temperature maybe a preset temperature value, and may correspond to a temperatureassociated with errors in the operation of the charging IC 110 and/orthe mobile device 100.

So long as the battery temperature remains less than the high thresholdvalue (S5440=NO), the direct charger 113 may be used to repeat methodsteps S210, S220 and S430. That is, until the battery temperatureexceeds the high threshold temperature (S5440=YES), the charging IC 110may continuously perform charging using the direct charger 113. However,when the battery temperature exceeds the high threshold temperature, thedirect charger 113 must take additional steps to reduce the batterytemperature.

Hence, the charging IC 110 may decrease the charging current I_(CHG)(S342), as previously described with reference to the embodiment of FIG.11 . When the charging current I_(CHG) is reduced, switching loss orconduction loss is also reduced and the amount of a current convertedinto heat decreases by an amount equal to the reduced loss. In thismanner the battery temperature may be reduced. As the direct charger 113decreases the charging current I_(CHG), the charging voltage applied tobattery also decreases. Accordingly, the charging IC 110 may request adecrease in the level of the external power signal provided by theexternal power unit 200.

After decreasing the charging current, the charging IC 110 may determinewhether the battery temperature is less than a low threshold temperature(S460). For example, the direct charger 1113 may compare the lowthreshold temperature with the battery temperature of the sensing datareceived from the fuel gauge 116. For example, when the battery 130 is alithium ion polymer battery, the low threshold temperature maycorrespond to a temperature at which a transportation rate ofelectrolytes of the lithium ion polymer battery may decrease and causemalfunction of the battery 130. When the battery temperature is higherthan the low threshold temperature, the direct charger 113 may determinethat the direct charger 113 may be continuously used and perform methodstep S420 again. On the other hand, when the battery temperature islower than or equal to the low threshold temperature, the direct charger113 may perform method step S470 to increase the battery temperature.

In method step S470, the charging IC 110 may increase the chargingcurrent I_(CHG). Because when the charging current I_(CHG) is increased,the switching loss or conduction loss also increases, and the increasedloss may be converted into heat and increase the battery temperature.

FIG. 14 is another waveform diagram illustrating relationships betweensignals during a battery charging process corresponding to the operatingmethod of FIG. 13 according to an embodiment of the inventive concept.

Referring to FIG. 14 , the charging IC 110 may perform charging usingthe direct charger 113 between time T1 and time T2 (a CC section of thebattery charging process). In particular, the charging IC 110 may detecta hardwire connection between the travel adaptor 210 and the mobiledevice 100 at time T1. The direct charger 113 may be used to directlyapply a charging voltage to the battery 130. Hence, the level of thecharging current I_(CHG) may be relatively high.

At time T2, the charging IC 110 may determine that the batterytemperature exceeds the high threshold temperature. When the batterytemperature obtained from the fuel gauge 116 is higher than the highthreshold temperature, the direct charger 113 may decrease the chargingcurrent I_(CHG). The operation of the charging IC 110 to decrease thecharging current I_(CHG) may be the same as method step S450 in FIG. 13.

At the time T3, the charging IC 110 may determine that the batterytemperature exceeds the low threshold temperature. When the batterytemperature obtained from the fuel gauge 116 is less than the lowthreshold voltage, the direct charger 113 may increase the chargingcurrent I_(CHG). The operation of the charging IC 110 to increase thecharging current I_(CHG) may be the same as the method step S470 of FIG.13 .

At time T4, the charging IC 110 may identify disconnection between theexternal power unit 200 and the mobile device 100. Although the batteryvoltage V_(BAT) has not reached the maximum battery voltage Vmax, thecharging IC 110 may perform charging using the switching charger 114 inresponse to the disconnection detection.

From the foregoing it may be understood that an operating method for thecharging IC 110 of FIG. 13 based on battery temperature may besimultaneously performed with the embodiment of FIG. 4A. And operatingmethod of the charging IC 110 may be simultaneously applied with theembodiments of FIGS. 6, 8, and 10 .

FIG. 15 is a circuit diagram further illustrating in another example thecharging IC 110 integrated circuit corresponding to a case in which awired or wireless input is short, according to an embodiment of theinventive concept.

Referring to FIG. 15 , the charging IC 110 may include the switchingcharger 114, the direct charger 113, and the battery 130. The chargingIC 110 of FIG. 15 may correspond to a modified example of the chargingIC 110 shown in FIG. 3A.

According to various embodiments, a wired input terminal TAIN and awireless input terminal WCIN may be shorted from each other. Forexample, when the charging IC 110 is embedded in an electronic devicethat does not support wireless charging, a charging efficiency may beimproved by having the wireless input terminal WCIN and the wired inputterminal TAIN shorted from each other. As the first transistor TR1 andthe second transistor TR2 are connected in parallel, when seen from thewired input terminal TAIN, a value of an equivalent resistor maydecrease, and efficiency of wired charging may be improved.

While the inventive concept has been particularly shown and describedwith reference to embodiments thereof, it will be understood thatvarious changes in form details may be made therein without departingfrom the spirit and scope of the following claims.

What is claimed is:
 1. A charging integrated circuit (IC) in a mobiledevice including a battery, the charging IC comprising: a switchingcharger including at least one inductor; a direct charger including atleast one capacitor; and a control circuit configured to detect aconnection between the mobile device and an external power unit and adisconnection between the mobile device and the external power unit,wherein: the switching charger and the direct charger selectivelyreceive an external power signal provided by the external power unit bythe connection between the mobile device and an external power unit,upon detecting the connection between the mobile device and the externalpower unit, the charging IC activates the direct charger and provides aconstant charging current to the battery using the direct charger, upondetecting the disconnection between the mobile device and the externalpower unit, the charging IC deactivates the direct charger, activatesthe switching charger, and maintains a battery voltage associated withthe battery using the switching charger, and the detecting of thedisconnection is identified by determining whether a response signalfrom the external power unit is received within a predetermined timesince the control circuit transmitted a request signal to the externalpower unit.
 2. The charging IC of claim 1, wherein the switching chargerand the direct charger are commonly integrated on a semiconductorsubstrate.
 3. The charging IC of claim 1, wherein: the connectionbetween the mobile device and the external power unit is made using auniversal serial bus (USB) type C interface, the charging IC furthercomprises a receptacle interface including a plurality of pins, and thecontrol circuit is further configured to communicate control informationwith the external power unit to control a level of the external powersignal using at least one configuration channel (CC) pin among theplurality of pins.
 4. The charging IC of claim 3, wherein the detectingof the connection between the mobile device and an external power unitis made in relation to the at least one CC pin upon a mechanicalconnection of the external power unit and the mobile device.
 5. Thecharging IC of claim 3, wherein the detecting of the disconnectionbetween the mobile device and an external power unit is made in relationto the at least one CC pin upon a mechanical disconnection of theexternal power unit and the mobile device.
 6. The charging IC of claim3, wherein: the mobile device comprises a system load having a powerrequirement met by the battery, and the control information communicatedto the external power unit controls the level of the external powersignal in response to the power requirement of the system load.
 7. Thecharging IC of claim 1, wherein a first charging efficiency provided bythe direct charger is greater than a second charging efficiency providedby the switching charger.
 8. The charging IC of claim 1, wherein theexternal power unit comprises at least one of a travel adaptor and awireless charger selectively providing the external power signal to themobile device.
 9. A method of operating a charging integrated circuit(IC) in a mobile device including a battery, the method comprising: upondetecting a connection between the mobile device and an external powerunit providing an external power signal, activating a direct charger andusing the direct charger to charge the battery with a sequence ofmultiple constant currents that each has a level of the same proportionto a respective one of a sequence of multiple levels of the externalpower signal, wherein each of the multiple constant currents has adifferent amplitude and the sequence of multiple constant currents isprovided to the battery immediately prior to charging the battery with aconstant voltage using a switching charger; and charging the batterywith the constant voltage during a constant voltage (CV) section of thebattery charging process.
 10. The method of claim 9, wherein thecharging of the battery during the CV section comprises deactivating thedirect charger and activating the switching charger to provide aconstant voltage charging of the battery.
 11. The method of claim 9,wherein: the charging IC comprises an interrupt control logic (ICL)having an internal resistor that selectively passes the external powersignal from the external power unit to the direct charger, and thecharging of the battery during the CV section comprises adjusting aresistance of the internal resistor to maintain a constant voltagecharging of the battery.
 12. The method of claim 9, further comprisingperforming a step constant current (CC) algorithm between thetermination of a CC section and the beginning of the CV section.
 13. Themethod of claim 12, wherein the performing of the step CC algorithmcomprises: determining whether a battery voltage associated with thebattery has reached a maximum battery voltage; upon determining that thebattery voltage has reached the maximum battery voltage, decreasing acharging current applied to the battery as a charging power; determiningwhether the charging current is less than a threshold current value; andupon determining that the charging current is less than the thresholdcurrent value, deactivating the direct charger and activating theswitching charger to provide a constant voltage to the battery duringthe CV section.
 14. The method of claim 9, wherein the CV sectioncomprises: obtaining battery temperature information; determining fromthe battery temperature information whether a battery temperatureexceeds a high threshold temperature; upon determining from the batterytemperature information that the battery temperature exceeds the highthreshold temperature, decreasing a charging current applied to thebattery; determining from the battery temperature information whetherthe battery temperature is less than a low threshold temperature; andupon determining from the battery temperature information that thebattery temperature is less than the low threshold temperature,increasing the charging current.
 15. The method of claim 14, wherein thebattery temperature information includes at least one of a temperatureof the battery, an internal temperature within the charging IC, anexternal temperature outside the charging IC, and an internaltemperature within the mobile device.
 16. A mobile device comprising: abattery embedded in the mobile device; and a charging integrated circuit(IC) chip configured to: charge the battery, using a direct charger,with a sequence of multiple constant currents that each has a level ofthe same proportion to a respective one of a sequence of multiple levelsof an external power signal provided by an external power unit, whereineach of the multiple constant currents has a different amplitude and thesequence of multiple constant currents is provided to the batteryimmediately prior to charging the battery with a constant voltage usinga switching charger, and thereafter charge the battery with the constantvoltage during a constant voltage (CV) section of the battery chargingprocess.
 17. The mobile device of claim 16, wherein the charging ICcomprises a control circuit configured to detect a connection betweenthe mobile device and the external power unit and activate the directcharger to charge the battery with the multiple constant currents. 18.The mobile device of claim 17, wherein the charging IC furthercomprises: a fuel gauge configured to detect an end of a constantcurrent (CC) section by comparing a battery voltage associated with thebattery with a maximum battery voltage, wherein upon detecting the endof the CC section, the control circuit deactivates the direct chargerand activates the switching charger to provide the constant voltage tothe battery during the CV section.
 19. The mobile device of claim 17,wherein the charging IC further comprises: an interrupt control logic(ICL) having an internal resistor and configured to selectively pass theexternal power signal from the external power unit to the directcharger; and a fuel gauge configured to detect an end of a constantcurrent (CC) section by comparing a battery voltage associated with thebattery with a maximum battery voltage, wherein upon detecting the endof the CC section, the control circuit changes a resistance of theinternal resistor.
 20. The mobile device of claim 17, wherein thecontrol circuit is further configured to perform a constant currentalgorithm to provide the sequence of multiple constant currents to thebattery.